The barred l, the doubled consonants, the long vowls marked with a colon (a:, i:, etc.) and the glottal stop spelled with ‘ are all diagnostic of Zuñi, along with the marked tendancy for the final word of the sentence to be rather long, since it’s the verb and carries a lot of information.

Barred l, doubled consonants, long vowels with colons, and glottal stops with ‘ are found in a wide variety of orthographies for languages in North America. Also many North American languages are SOV with the verb at the end, and many also feature complex verbal morphology. So none of those features are diagnostic.

The presence of “ch” but lack of something like “j” being a corresponding voiced or unaspirated postalveolar affricate is interesting. Especially if “Dewusu’” means “Jesus” where we’d expect a voiced or unaspirated affricate initially. Another related gap seems to be with “ts” and no “dz” or the like, so perhaps the language lacks a voicing/unaspirated distinction apically.

Neither Ahtna nor Tlingit are this language. Most Athabaskan languages have tone and so use a diacritic above vowels. Many have nasalization as well so that the ogonek appears below vowels. Also, no Athabaskan language uses colons for length, although Eyak is written with a single dot for length. Finally, although it does lack tone, Ahtna has a velar-uvular distinction using an orthographic opposition of “c” and “k” which doesn’t appear in this text. (Compare Denaʼina with “k” and “q”.) Tlingit has a similar distinction where the orthograhphies use either a digraph with “h” or an underscore diacritic to represent the uvulars. Also the Tlingit orthography used in Alaska does not use “ł” because there is only a voiceless lateral fricative so “l” serves this purpose.

This particular combination of features taken together *is* diagnostic, esp. with the vocabulary and the verb forms ending in -nna, a future / non-past conditional ending. Even without the latter items, I doubt you’ll find another N. American language with exactly those orthographical features. Diagnostic, in any case, does not necessarily mean “definitive”.

nomad and fiosachd are right – the answer is Zuni/Zuñi, a language isolate spoken in western New Mexico and eastern Arizona.

The text comes from the Bible, Acts 2:18-20

18. And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy:
19. And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke:
20. The sun shall be turned into darkness, and the moon into blood, before the great and notable day of the Lord come: